title: N-n-propyl-norapomorphine: an extremely potent stimulant of dopamine autoreceptors.
abstract: N-n-propyl-norapomorphine (NPA) is 10-20 times more potent than apomorphine in producing hypomotility and inhibiting both striatal and limbic dopamine (DA) synthesis and the firing rate of nigral dopaminergic cells in rats. The threshold subcutaneous doses of NPA and apomorphine to significantly inhibit motor activity or DA synthesis are 1.25 and 24 microgram/kg, respectively. The intravenous ED 50 of NPA to inhibit dopaminergic firing is 0.36 microgram/kg and that for apomorphine is 9.1 microgram/kg. The above effects of NPA, as those of apomorphine, are antagonized by haloperidol and, stereospecifically by (--) sulpiride.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004298:Dopamine / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005625:Frontal Lobe / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009434:Neural Pathways / Q000187:drug effects; D009714:Nucleus Accumbens / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D013268:Stimulation, Chemical; D013378:Substantia Nigra / Q000187:drug effects
chemical_list: D011954:Receptors, Dopamine; C009074:N-n-propylnorapomorphine; D004295:Dihydroxyphenylalanine; D001058:Apomorphine; D004298:Dopamine